DX10 Battery Contact Spot Welder Teardown

RE: DX10 Battery Contact Spot Welder Teardown

DAB — Thu, 22 Sep 2022 18:23:28 GMT

Very interesting.

Are you going to give it some use to see how it holds up over time?

RE: DX10 Battery Contact Spot Welder Teardown

shabaz — Thu, 22 Sep 2022 10:42:28 GMT

I've been googling today and found that the DX10 is also sold as a 'SeeSii" product, there is a video here (it is discussed in three videos by the presenter).

There is also interestingly a video regarding a 'Sequre SW2' product that is similar with a few slight differences. The board design looks like an iteration of the DX10. The manufacturer in this case has bolted the battery tabs, and used thick copper plate on the board. The bolted tabs looks interesting, I would have expected clamping plates would be needed, but there are not any.

This is a snippet from a screenshot from that video.:

The video also shows the other side:

The display and software is slightly different, but the rest looks very similar.

The Sequre SW2 is more expensive (about £76 versus £32 for the DX10). I don't know if I would have bought that just for occasional use, but it is more likely to work out of the box since it already has the copper plate.

Having seen what the Sequre model looks like, I will add a bit more copper sheet on top, just in case it makes any more difference, although now I believe the power output is at a decent level.

RE: DX10 Battery Contact Spot Welder Teardown

shabaz — Thu, 22 Sep 2022 00:55:41 GMT

There's good news and bad news : )

I did a test using an AA Alkaline cell.

When I tried the DX10, at 70% power, the welded tab came off easily. I upped the power to 90%, and it wasn't much better.

I decided that the metal rods are clearly a manufacturing error. Someone must have specified copper, and instead some other material was used (it definitely isn't copper, it's way too stiff and the wrong colour).

Anyway, long story short, if the rods are removed, and replaced with copper (I used copper sheet, 0.25 mm thick is easy to cut with scissors, followed by 1.6 mm dia copper wire (it was enamelled wire but I sanded off the enamel), then it works much better.

Here is what I did to the device (and a similar thing on the other side):

Now, still at 90% power, the weld appears much better, it looks like this:

If I try to pull the tab off, it rips the metal tab, i.e. the weld is now much stronger. I tried this a couple of times (on two cells). I still need to experiment more to find the optimum power, but this is now a good start.

Removal of the metal rod and soldering on the new copper is not a pleasant task, because there's a high risk of shorting something. It also needs a large soldering iron bit. But there is an improvement for sure. Maybe there are simpler ways to achieve the same result (e.g. solder braid in an insulator alongside in parallel without removing the metal rods) but that would require more experimentation.

It would be good to let the manufacturer know that their factory is using the wrong metal, but I don't know who the manufacturer is.

RE: DX10 Battery Contact Spot Welder Teardown

ralphjy — Wed, 21 Sep 2022 20:30:20 GMT

Look forward to a “road test”. What are you planning to weld with this unit?

RE: DX10 Battery Contact Spot Welder Teardown

scottiebabe — Wed, 21 Sep 2022 18:42:57 GMT

Wonderful photos! Interesting product.

I suspect the discrete gate driver is referenced to the DW01's switched ground. So when the DW01 UVLO, the gates of the power fets are likely floating... As you suggest, storing the unit with the welding leads disconnected is very good advice!

RE: DX10 Battery Contact Spot Welder Teardown

genebren — Wed, 21 Sep 2022 18:10:26 GMT

This an interesting product. I would greatly interested in seeing how well it works, when you get around to testing it.

Thanks for sharing.

(It is crazy how some people deal with the hazard of shorting out a Li-Ion cell, including not at all. As a part of receiving FDA approval on products, we needed to document how a product would deal with a direct short, or as near of a direct short that we could apply safely. In a hand held product with a Li-Ion cell, we would write special software to go into a 'test' device to cause a short with a very high power, low resistance MOSFET (or multiple) across the battery with a countdown timer so you could start the device and place it safely in a metal container. The smoke and melted plastic, PCB, components that resulted in this test were very impressive and left you with the impression that you must do everything you can do to prevent this from happening. We would repeat this test, with and without our internal protections in place to make sure that the protections would work and that even if they failed the unit would not explode or burst into flames. In all of the cases that we ran, the battery leads, while heavy enough in gauge to pass bursts of energy in excess of 100A, eventually acted as fuses and melted to prevent the battery from reaching critical conditions.)